Photometric apparatus for a camera

ABSTRACT

A photometric apparatus of a camera for carrying out a multi-segmented photometry by receiving object light reflected at a film or the shutter, include a plurality of photometric elements which are disposed at positions to respectively receive reflected light from the film or the elements, are segmented in accordance with each of regions segmenting the object field, corresponding to regions of the film or the shutter, and are arranged in parallel in a predetermined direction within a mirror box so as to respectively receive light reflected with diffusion angles less than a predetermined angle from respective reflection regions of the film or the shutter. Photometric lenses are respectively positioned between the reflection regions and the photometric elements, corresponding to the photometric elements, so as to respectively direct the object light reflected at the reflection regions to the plurality of photometric elements, and are arranged in parallel so as to restrict incidence of reflected light on the photometric elements from other reflection regions.

This is a division of application Ser. No. 560,745, filed Jul. 31, 1990,now U.S. Pat. No. 5,231,448.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photometric apparatus capable ofmulti-segmented photometry and more particularly to a photometricelement for performing photometry when receiving object light reflectedat the film surface or the shutter blind surface.

The present invention also relates to a photometric apparatus used in aTTL automatic light adjusting camera, and more particularly to that usedin a camera having a focal plane shutter and an automatic lightadjusting unit to be used at the time of photographing using a flash.

The present invention furthermore relates to a photometric apparatus ina camera having a light emission control unit.

2. Related Background Art

A photometric apparatus capable of so-called multisegmented photometryhas been known in which the image plane is divided into a plurality ofphotometric regions and photometry is effected for each of thephotometric regions. In this type of photometric apparatus, a pluralityof photometric elements are arranged in a mirror box correspondingly tothe photometric regions, and photomerry is performed by directing,respectively for each photometric region, the object light reflected atthe shutter surface after passing through the photographing lens to saidplurality of photometric elements via the photometric lens. Also, as alight adjusting device of an electronic flash unit, a device has beenknown in which the object light after passing through the photographinglens is caused to be reflected at a film surface, and light adjusting isperformed by similarly directing the reflected light to a plurality ofphotoelectric elements, respectively, via the photometric lens.

In this specification, the term "photometry" is used to also signify thelight adjusting in this type of electronic flash device.

There are however problems, as will be described below, in theconventional photometric apparatus because of the fact that a pluralityof photometric elements are concentrated around a single point and thatonly a single photometric lens is provided.

FIG. 1 show the positional relationship, in a light adjusting device asdescribed above, seen from the top of a camera, among a photometric lens1, a photometric element 2 (a plurality photometric elements denselyarranged around a single point) and film surface FI. In this figure, l1denotes light entering from photometric regions, being incident upon thefilm surface, l2 denotes a regularly reflected light of the incidentlight l1, and l3 denotes dispersedly reflected light which is actuallyincident on the photometric element 2. In this case, the angle betweenthe reflected light l3 and the regularly reflected light l2 (hereinafterreferred to as diffusion angle) θ is rather large, to be θ1. In general,the smaller the diffusion angle θ, the more intensified is the lightincident on the photometric element 2, and, when the diffusion angle θis large such as θ1, the amount of light received by the photometricelement 2 is reduced because of the weakness of the light intensity ofthe reflected light l3. When these luminous quantities are less than thedetectable limit of the photometric element 2, photometry becomesimpossible.

Although the above described problem may be solved by increasing thediameter of the photometric lens 1 so as to increase the amount of lightto be received, an increase in the size of the camera becomesunavoidable.

Furthermore, in FIG. 2 which describes conventional light adjustingoperation, at the time of picture taking with a flash by using anelectronic flash device (not shown), the luminous flux reflected fromthe object body is reflected at the film surface FI after passing thephotographing lens LE, and the light due to the diffused reflection isdirected to the photometric element 2 of the photoelectric conversiontype through the photometric lens 1.

This photometric element 2 includes a main body 3, light receivingportion (not shown) fixed to the body 3 and a plurality of lead frames 4extended from the body 3, and the body 3 is arranged with an inclinationto the film surface FI. Thus the irregularly reflected light is receivedby the light receiving portion 5 after passing through the photometriclens 1, and a circuit portion (not shown) in the body 3 generates anelectrical signal in accordance with the amount of the received lightwhich is input into a light adjusting circuit, not shown, through thelead frames 4. The light adjusting circuit integrates the input currentand, when the integrated amount reaches a predetermined amount, outputsa light emission stop signal so as to stop the light emission of theelectronic flash device.

However, when an object with a high reflection rate, such as agold-leafed folding screen, exists behind the subject (person) at thetime of photographing using a flash, because of the fact that the lightadjusting is effected on the basis of the reflected light, it may resultin a photograph of so-called "under exposure" where the face of aperson, the main subject, is darkened all over. In accordance with oneaspect of the present invention, for the purpose of obtaining anappropriate exposure at any photographing condition at the time ofphotographing with a flash, in the specification of Japanese PatentApplication No. 1-204300 in which the film surface FI is segmented forexample into five regions 6a˜6e as shown in FIG. 3 and the reflectedlight from each region is received by each of separate light receivingportions 7a˜7e so that the light adjusting is effected on the basis ofthe results of light reception at respective portions.

Referring to FIG. 3, in other words, the lights reflected from theregions 6a, 6b of the regions of the film surface FI are respectivelyreceived by light receiving portions 7a, 7b, through a photometric lens8c, while the reflected light from the region 6c is received by a lightreceiving portion 7c through a photometric lens 8b. Furthermore, thereflected lights from the regions 6d, 6e are received by light receivingportions 7d,7e through a photometric lens 8a.

It should be noted that the term "photometry" in this specification isused to refer to both the so-called ordinary photometry for the exposurecontrol and light adjusting of an electronic flash device as describedabove.

In the case of using a photometric element as above, however, a certaindistance or more is necessary between the photometric lens and the lightreceiving portion to obtain a conjugate relationship between the lightreceiving portion and the film surface FI. In addition, the integrationof the light receiving portion and the circuit portion, for the purposeof improving the light adjusting precision, results in an enlargement ofthe element and an increase in the number of lead frames, which can leadto a disadvantage that the camera will be increased in size because ofthe increase in the arrangement space for the photometric element in thecamera body. In particular, the above mentioned problem is more seriousin nature when employing the segmented photometric (light adjusting)system as described above, because the photometric element itself mustbe enlarged due to an increase in the number of the light receivingportions.

Further, because of the increasing availability of auto-focus (AF)systems of a camera in the recent years, an AF sensor module is morelikely to be placed at the bottom of a camera body. From the viewpointof the coexistence of such AF sensor module and the above describedphotometric element, the increase in the space for the disposition ofthe above described photometric element becomes even moredisadvantageous.

Conventionally, furthermore, a TTL auto light adjusting control deviceused for the flash photographing of a camera having a focal planeshutter is provided with a single light receiving element at a positionfrom which a portion or the whole of film surface can be supervised, andthe flash apparatus is caused to emit light after fully opening theshutter. Thus, by effecting a photoelectric transfer of the light due tothe reflection of an image in the object field at the film surface andby comparing the signal corresponding to the integrated amount of thelight with a predetermined amount of light, the amount of light to beemitted from the flash apparatus is controlled so as to secure a certainluminosity at the film surface.

Moreover, it is also known to construct a photometric means for steadylight in such a manner that the photometry is effected by segmenting theobject field into a plurality of regions so as to previously detect thestate of the object under the steady light level, and a correction onthe basis of the result is made with respect to the light amount levelto be controlled at the time of a flash photographing.

Since, however, the conventional art controls the emitted light amountfrom a flash apparatus as an average within a predetermined region ofthe film surface which is looked over by the light receiving element atthe time of the light adjustment for flash photographing to obtain acertain exposure level, a wide variance in the resulting pictures iscaused depending on the condition of the object. When for example aflash photographing is effected, for a main object which occupies only asmall portion of the image field and which is located on a deeply spacedbackground, by a camera in which the range supervised by the lightreceiving element is the entire film surface, the light emissionquantity accordingly controlled has an effect of an over-exposure forthe main object because there is a wide portion at which the light fromthe flash apparatus is not reflected.

On the other hand, when using a camera in which the range supervised bythe light receiving element is a center portion of the film surface, theexposure for the main subject may be erroneous if a flash photographingis effected under a condition where the main object is out of the centerportion and the center portion is occupied by an object which is locatedat a distance different from that of the main object.

Furthermore, when the configuration is such that the light emissionlevel to be controlled at the time of a flash photographing is correctedon the basis of the condition of the object which is previously detectedunder a steady light level with the photometry using photometric meansfor steady light by segmenting the object field into a plurality ofregions, an appropriate correction is not likely to be effected becauseof the fundamental difference between the object image under steadylight and the object image under flash light. In an extreme case, forexample, necessary information is hardly obtained for the night-timephotographing with the steady light photometry and the light adjustingare after all without any correction, whereby the above describedproblems remain unsolved.

As one of the proposals to eliminate the problems as above, JapanesePatent Laid-Open No. 60-15626 has been provided. This discloses a cameraincorporating a stroboscope of the so-called externally light-adjustedtype. In this configuration, the image field is divided into tworegions, the center portion and the peripheral portion, to detect thedifference in the output of these two regions by a preliminary flash,and, on the basis of the amount of such difference, one with a largeroutput is determined to be the main object if the difference exceeds apredetermined amount so that only the center or only the periphery isalmost exclusively subjected to the light adjusting for the main flashat the time of photographing, while both are subjected to the lightadjusting on an average basis if the difference is less than thepredetermined value. Thus, "the stroboscope light is controlled so thatan appropriate exposure is achieved at all times by eliminating theinfluence due to the difference in the composition of the scene to bephotographed" and in an embodiment, a detection system for the objectfield using a preliminary flash and a detection system for the lightadjustment control at the time of main flash are provided as separatesystems from the photographing optical system.

However, in a system according to the above described conventionalexample, of the two regions divided at the time of preliminary flash,the region with larger output is always decided to be the region atwhich the main object is located. Therefore, when for example agold-leafed folding screen is placed right behind the subject person,the output is larger for the region without the subject person, and, ifthe stroboscope light is adjusted by emphatically effecting photometryfor this region at the time of main flash, a photograph will resultwhere the subject person is underexposed. In other words, the abovedescribed invention is not only incapable of solving the conventionalproblems due to the difference in the reflectivity of the object bodybut also with such a disadvantage that the stroboscope may be controlledreversely, to a wrong direction.

Furthermore, since the detection systems in the disclosed example of theabove described invention are of the type externally adjusting thelight, it cannot be employed in a camera of which lenses are changeable,because the segmenting configuration of the object field in thedetection system and the segmenting configuration of the object field onthe film surface are changed depending on the type of lenses due todifference in the image angle.

Still furthermore, FIG. 4 shows the configuration of a conventionallyknown TTL auto light adjusting camera. The condition at the time ofobservation through the finder is such that the luminous flux (steadylight) after passing through the photographing lens LE of a single-lensreflex camera is reflected by a mirror 10 at its mirror-down state asshown by the broken line and a portion of which is directed to aneye-lens 13 via a screen 11 and a pentagonal prism 12 while anotherportion of which is directed to an exposure calculating photometricelement 15 via a photometric lens 14. And the condition of the camera atthe time of photographing is such that, when for example a flashphotographing is to be effected at an adverse light condition under aclear sky, both the steady light and the light emitted from a flashapparatus 16 and reflected by the object body pass through thephotographing lens LE and reach the film surface FI through an openedshutter 17 because the mirror 10 is retracted to the position as shownby a solid line. The light reflected at the film surface FI is directedto a light adjusting photometric element 7 via a photometric lens 8.

In this configuration, the photometric output of the exposurecalculating photometric element 15 is used in determining the exposurevalue. Further, the photometric output of the light adjustingphotometric element 7 is used in determining the timing for stopping theemission of the flash apparatus 16. In other words, the emission isstopped when the integrated value of the output of the light adjustingphotometry reaches a predetermined light amount.

In such a conventional TTL auto light adjusting camera, the emissionamount may be affected depending on the percentage of the image fieldoccupied by the main object (such as persons) or existence/nonexistenceof a highly reflective object such as a gold-leafed folding screen, andthe light adjusting may not be properly effected. Thus as proposed inthe specification of commonly assigned Japanese Patent Laid-open No.2-87127 photometry is effected by segmenting a light adjustingphotometric element 7 into a plurality of regions; the reflectivitydistribution (luminance distribution) of the object field is obtainedfrom the photometric output of the light adjusting photometric element 7by executing a preliminary flash prior to the main flash, and the outputfor each photometric region is corrected by weighting in accordance withsuch reflectivity distribution to accurately adjust the light.

However, since such a TTL auto light adjusting camera is designed toperform a preliminary flashing for any flash photographing regardless ofthe set aperture value so as to effect a correction by means ofweighting, an appropriate light adjusting may not be achieved at thetime of using a small aperture value because the photometry by the lightadjusting photometric element 7 based on the preliminary flashing cannotbe accurately performed due to an insufficiency of light.

Still furthermore, when using a conventional camera such as describedabove in the dark such as during a night, the following problems arise,for example when the main object is a person, even if such as the imageangle of the photographing angle and the distance to the main object arethe same. Specifically, in cases:

(1) where the percentage of the image plane occupied by the persons isdifferent due such as to a difference in the number of persons or adifference in the image composition;

(2) where in a room there is a difference in the distance from theperson to the,background wall;

(3) where a hollowness-like state occurs or the background conditiondiffers when there is a wall at the background or when the background issuch as a landscape; or

(4) where a difference occurs due to existence/nonexistence of a highlyreflective portion such as a wedding cake or a gold-leafed foldingscreen;

there has been a problem that a difference in the emission amount occursat the time of TTL light adjusting control due to such differences inthe condition.

Further in the case such as during the daytime where it is well-lighted,if a TTL light adjusting is effected by using the photometric element 7when an extremely bright object such as the sun enters in a portion ofthe image plane, there has been a problem such that an underexposure ofthe main object occurs because of insufficiency of light provided by theflash apparatus 16.

This is because the TTL light adjusting system is based on the principlethat the steady light and the light, emitted from the flash apparatus16, returning as the result of reflection at the object body are at thesame time indiscriminately subjected to the photometry so as to stop theemission of the flashing means upon the detection of the fact that suchamount has reached a predetermined amount. Thus, if a highly brightobject occupies a portion of the image plane so as to increase thesteady light component, the amount to be emitted by the flash apparatusis accordingly controlled to a smaller amount.

SUMMARY OF THE INVENTION

An object of the present invention is to increase the amount of light tobe received by a photometric element without increasing the diameter ofa photometric lens.

Another object of the present invention is to dispose photometricelements so that the increase in the size of a camera body may berestricted to the minimum.

A further object of the present invention is to eliminate the variancein the exposure for the main object which occurs due to a difference inthe condition such as the position and reflectivity of the object bodyat the time of flash photographing even when using a camera such as asingle-lens reflex camera of which lenses are changeable.

A still further object of the present invention is to provide a TTL autolight adjusting camera which employs a system for correcting thephotometric output at the time of light adjusting in accordance with thereflectivity distribution in the object field, and which is capable ofan appropriate light adjusting even when the aperture is controlled tobe small.

In view of the problem that a conventional TTL light adjusting system islargely affected by the main object and its background, a still furtherobject of the present invention is to solve this problem and to providea light emission control device, of a camera capable of TTL lightadjusting operation, which is without exception able to effect anappropriate light adjustment.

A description will be given below with reference to FIG. 5A showing afirst embodiment. The present invention is applicable to a photometricapparatus of a camera in which the image plane is segmented into aplurality of photometric regions and a plurality of photometric elements18a˜18e are arranged correspondingly to each photometric region in amirror box MB (see FIG. 6) and which effects photometry by directing,after passing through the photographing lens, the light reflected by thereflecting regions 6a˜6e corresponding to the photometric regions at thefilm surface FI or at the shutter surface respectively to the pluralityof photometric elements 18a˜18e via photometric lenses 19a˜19e. And thetechnological problem as described above is solved by arranging inparallel in a predetermined direction said plurality of photometricelements 18a˜18e so that they receive the light reflected at thereflecting regions 6a˜6e, with angles less than a predetermineddiffusion angle, and by arranging in parallel in a predetermineddirection a plurality of photometric lenses 19a˜ 19e corresponding tothe plurality of the photometric elements 18a˜18e so as to restrict theincidence on each photometric element of the reflected light from otherreflecting regions.

Since both the photometric elements 18a˜18e and the photometric lenses19a˜19e are arranged in parallel in a predetermined direction, they donot require a large space in the narrow interior of the mirror box anddo not cause an enlargement in the size of the camera.

In this way, the object body light reflected at the reflecting regions6a˜6e such as of the film surface FI is caused to be incident on theplurality of photometric elements 18a˜18e via the photometric lenses19a˜19e. The light incident on each of the photometric elements of thereflected light from other reflecting regions is restricted by means ofthe photometric lenses 19a˜19e, and each of the photometric elements18a˜18e respectively receives the reflected light reflected at thereflecting regions 6a˜6e at angles less than the predetermined diffusionangle. Thus the intensity, i.e., the amount of the light incident oneach of the photometric element is increased compared to a conventionalconfiguration, and it is possible to accurately perform the photomerry.

A description will now be given with reference to FIGS. 13 and FIGS.14A, 14B which show a second example. The present invention may beapplied to a photometric element of a camera having: a body 22 of thephotometric element 21 disposed at the bottom of the camera body 9 or atthe upper portion of the AF sensor module 20 placed at the bottomthereof, inclined at an acute angle with respect thereto, and with aninclination to the film surface FI or to a shutter blind surface; lightreceiving portions 21a˜21e (see FIG. 14A) which are fixed on the body 22and receive the object body light reflected, after passing through thephotographing lens LE, at the film surface FI or at the shutter blindsurface; and a plurality of lead frames 23 which are extended from thebody 22 to transmit electrical signals in accordance with the amount oflight received by the light receiving portions 21a˜21e.

The above described technological problems are solved by making thelower surface 22b of the body 22 generally parallel to the bottomsurface of the camera body 9 or to the upper surface 20a of the AFsensor module 20 and by extending the signal transmitting lead frames 23to a portion other than the lower portion of the photometric elementbody 22.

By the configuration as described above, it is possible to reduce thespace necessary for the disposition of the photometric element withinthe interior of the camera body 9, and an increase in the size of thecamera may be controlled to the minimum.

Furthermore, the present invention provides the following configurationfor an auto light adjusting apparatus in order to achieve theaforementioned object.

A plurality of photoelectric conversion means are provided at a positionfrom which the film surface can be supervised such that photometry ispossible by segmenting the subject field into a central portion and aplurality of peripheral portions; the flash apparatus is caused to emita preliminary flash immediately before the opening of the focal planeshutter so as to catch the light reflected at the shutter blind surfaceof the object image caused by such flash light; and the amountrespectively integrated is detected as the object field reflection ratefor each region due to flash emission. By synthetically processing thedetected object field reflection information for each region, the degreeof weighting for each segmented region is decided so as to achieve themost appropriate exposure for the main object. Subsequently, the flashapparatus is caused to emit a main flash immediately after the openingof the shutter and the light reflected at the film surface is receivedby the same plurality of photoelectric conversion means as describedabove so that an integration by means of addition is performed aftereffecting the previously decided weighting for their outputs, and theresult is compared with a predetermined value to decide the timing atwhich the emission of the flash apparatus is to be stopped, and thelight adjusting for the main flash is completed.

Furthermore, the weighting means of the auto light adjusting controldevice according to the present invention sees whether there is a brightregion at which the object field has a reflection rate exceeding anupper limit value and whether there is a dark region having a reflectionrate less than a lower limit value. And, if there is seen any brightregion or dark region, such bright regions and dark regions are ignoredand a weighting value is calculated for each of the rest of the regions,while, if neither a bright region nor a dark region is seen, weightingvalues are calculated respectively for all the regions.

Light adjusting control sequence of a fundamental auto light adjustingdevice of the present invention will now be described by way of FIGS.18˜20.

Referring to FIG. 18, after releasing the shutter, a mirror up andstopping down operation is effected at step S1. Preliminary flash bymeans of the flash apparatus, i.e., an emitting operation before thefilm exposure by a main flash is then carried out at step S2. At stepS3, the reflected light, from the object field, of the light due to thepreliminary flash is caused to be reflected at the shutter blind surface(a surface having a reflection characteristic almost identical to thatof the film surface), and is metered by the segmented light receivingelement before a main flash. A light adjusting operation by means of thelight receiving element is carried out also in this preliminary flash,and, when the amount of the flash emitted reaches a predeterminedamount, an emission stop signal is output to end the preliminary flash.As a result, since the reflection rate distribution of the object fieldmay be detected by the preliminary flash before the emission of mainflash, the position of the main object within the object field may bepredicted with a high certainty by processing the photometric output andan appropriate control is possible if the main flash is controlled bytaking such a reflection rate distribution into the consideration.

At step S4, for a plurally-segmented light receiving elements to be usedfor light adjustment in the main flash, a weighting value is assigned toeach light adjusting light receiving element on the basis of thedistribution of the reflection rate within the object field detected bythe preliminary flash, i.e., the gain from the light receiving elementoutput is changed accordingly. Note that such a light adjusting lightreceiving element is segmented into the same configuration as the lightreceiving element used in measuring the reflection rate distribution andmay constituted by a light receiving element which is used for both thereflection rate measurement and the light adjustment or there may be twoindependent light receiving elements for these purpose.

Since, in steps S1˜S4, a preliminary flash, reflection rate distributiondetection and calculation of weighting values are performed rapidlyimmediately before the shutter is opened at step S5 so that only a fewmsec time interval is necessary between the preliminary flash and thethe main flash to be performed at step S6, the fact that the emissionhas actually occurred twice is not sensed and a better impression isgiven even when a person is the subject to be photographed. In addition,in the case of using a single-lens reflex camera, the fact that the timeinterval between the two emissions is short leads to an advantage thatthe so-called time lag, between pressing of the shutter release buttonand opening of the shutter, is almost unchanged.

At steps S7,S8, the main flashing operation by the flash apparatus iscarried out in which a plurality of segmented light receiving elementsfor the light adjusting to which weighting values are assigned on thebasis of preliminary flash receive the reflected light from the filmsurface, and the signals from the plurality of segmented light receivingelements are integrated by means of integrating means and, when apredetermined integration amount is reached, an emission stop signal isoutputted to complete the light adjusting.

Next, an actual method (algorithm) by which weighting values for theregions segmented at the time of the main flash are determined from thereflection rate distribution of the object field obtained from thepreliminary flash will be described hereinafter by way of FIGS. 19, 20and 4.

FIG. 19 is a block diagram showing a circuit which determines weightingvalues by the preliminary flash.

FIG. 20 is a flowchart showing the process through which weightingvalues for the segmented regions are determined. Note that the flow asshown in FIG. 20 may be programmed into a microcomputer or the like.FIG. 4 is a cross section of a camera.

First of all, when at step S12 the release button 24 (FIG. 19) of thecamera is released, the main mirror 10 (FIG. 4) is brought into amirror-up state and at the time the aperture of the lens is stopped downto a photographing aperture value. Program then proceeds to step S13 atwhich the preliminary flash is emitted by the flash apparatus 16. Thelight of the preliminary flash reflected from the object reaches thephotometric element 7 after passing through the photographing lens LE(FIG. 4) and reflected at the shutter (FIG. 4).

The element surface of the photometric element 7 is segmented into fiveregions 7a˜7e as shown in FIG. 19 so that the object field is segmentedinto five regions in measuring the light. A photometric currentoccurring at each region is transmitted to weighting value calculationmeans 26 where the integration of the reflected light from the objectbody is carried out at step S14. The integrated amount of each elementis set as Cn (n=1˜5).

At step S15, the reflection rate distribution Rn is obtained from Cn asfollows: ##EQU1##

During steps S16 to S22, operations are carried out to extractphotometric regions at which the reflection rate distribution Rn (n=1˜5)is very high (Rn>0.8) and photometric regions at which it is very low(Rn<0.1) and these are to be cut off. The reason for this is that, at aphotometric region with a very high Rn, there is presumably behind themain object (a person) an object such as a gold-leafed folding screen ora white wall which gives an adverse effect on the TTL light adjusting.Further, at a photometric region with a very low Rn, the background ofthe main object (a person) is presumably for example a landscape whichmay evade photometry, the result being another factor to cause anadverse effect to the TTL light adjusting process.

In such cutting out, the reflection rate distributions Rn (n=1˜5) forthe cut out regions are replaced by 0 and are not counted in thesubsequent calculations.

At step S23, by using the reflection rate distributions Rn after thecut-out operation, weighting values Dn are calculated as follows:##EQU2##

The program then proceeds to steps S24 and S25 at which said weightingvalues Dn are converted correspondingly into voltages En as follows:

    En=K(1-Dn)Er                                               (3)

and are outputted to a weighted light adjusting circuit 3. Note that "K"represents a value corresponding to an ISO information and is inputtedat step 24 by means of an ISO information input means (FIG. 19).Further, Er is a predetermined constant voltage.

Upon the inputting of the voltage En corresponding to the weightingvalue into a weighting light adjustment circuit 28, the main flashing bythe flash apparatus 16 is carried out at step S26. The reflected lightfrom the object body due to the main flash reaches the photometricelement 7 as shown in FIG. 4 through the lens LE (FIG. 4), reflected atthe film surface FI (FIG. 4) and through the photometric lens 8 (FIG.4).

The reflected light metered in segments by the photometric element 7 isintegrated at step 27, being weighted at the weighting light adjustmentcircuit 28 (FIG. 19). Thus, when the total of the integrated amount forthe five regions reaches a predetermined amount, the emission stopsignal is supplied and the emission by the flash apparatus 16 is stoppedby way of a flash control means 29, and the program then proceeds to itsend at step S28.

As is apparent from the foregoing description, when for example there isan output only from the center one of the segmented regions at the timeof photographing during a night and there are no outputs from the otherperipheral segments, the weighting is carried out such that only thecentral segmented photometric element 7c is used in the lightadjustment. Furthermore, when for example one region is outstandinglybright though outputs are detected from all or most of the regions, theprobability of this region being the main object is presumed to be verylow and the weighting is carried out in such a manner that this one doesnot contribute to the weighting, thus improving the probability of themain object being appropriately exposed.

The fundamental auto light adjusting sequence of an auto light adjustingcontrol device of the present invention may be carried out as describedabove.

The present invention will now be described by way of FIG. 28. Thepresent invention comprises: a flash apparatus 16 capable of both apreliminary flashing to detect the reflection rate distribution of theobject field and a main flashing for the flash photographing of theobject field; a light meter 30 which, by segmenting the object fieldinto a plurality of regions, meters each of the reflected lights fromsaid plurality of regions due to the flash apparatus 16 and outputsrespective photometric signals; a weight amount calculator 26 forobtaining the weight amount to adjust the photometric signals providedby light meter 30 at the time of main flashing on the basis of thephotometric signals form the light meter 30 obtained at the time of thepreliminary flash; a light adjuster 28 for stopping the emission of theflash apparatus 16 in accordance with the photometric signals from thelight meter 30 at the time of the main flashing and with the weightamount from the weight amount calculator 26; an aperture set device 31for setting the aperture value before the photographing operation; adiscrimination device 32 for checking if the set aperture value providedby the aperture set device 31 exceeds a predetermined value; and a flashcontroller 29 which, when it is seen by the discrimination device 32that the set aperture value exceeds the predetermined aperture value,carries out the main flashing without a preliminary flashing and which,when it is seen by the aperture set device 32 that the set aperturevalue is smaller than the predetermined aperture value, carries out themain flashing on the basis a preliminary flashing.

When it is seen by the discrimination device 32 that the set aperturevalue is larger than a predetermined aperture value, it also possible toadjust the photometric output on the basis of a predetermined reflectionrate distribution. Or, when the aperture value calculated by aprogrammed exposure mode is larger than a predetermined aperture value,the set aperture value may be limited to the predetermined aperturevalue.

According to the present invention, when the set aperture value is lessthan a predetermined value, i.e., in the case where the aperture isrelatively large, a preliminary flash is carried out and weight amountsrelated to the reflection rate distribution of the object field arecalculated so as to adjust the light at the time of main flashing inaccordance with such weight amounts. Thus the photometric output of theregions with high reflection rate within the object field are lesslikely to take a part in determining the emission amount during thelight adjustment and a larger part is taken in determining the emissionamount with a decrease in reflection rate. However the amount of lightreaching the photometric elements is small when the aperture value issmall and the output value at that time is not reliable. Thus, when theaperture value is regarded as small, the light adjusting using thereflection rate distribution obtained from the preliminary flash, i.e.,on the basis of weight amounts is not carried out.

Further, according to the present invention, at the time of using asmaller aperture, the photometric output may be corrected in accordancewith a predetermined reflection rate distribution.

Furthermore, according to the present invention, the set aperture valuemay be limited to a predetermined value even when the aperture valuecalculated by a programmed exposure mode is a small one so that acorrection of the photometric output may be carried out at all times onthe basis of the reflection rate distribution of the object field toeffect a more appropriate light adjusting for the object.

In a further development, a light emission control device according tothe present invention comprises:

a flash controller for selectively causing the flash apparatus to carryout both a main emission for the exposure and a preliminary emission fordetecting the luminance condition of the object field in advance to themain emission;

a light adjusting device, having segmented light adjusting elements, forcontrolling the emission of the flash apparatus on the basis of theoutput of the light adjusting elements;

a photometric apparatus for metering the light from the object field;

a field categorization apparatus for categorizing the luminancecondition of the object field into at least a first condition and asecond condition by using the output from said photometric apparatus;and

a controller which, when the object field is categorized as being insaid first condition by the field categorization means, causes saidflash controller to prohibit a preliminary emission by said flashapparatus and executes weighting process for the outputs of saidsegmented light adjusting elements on the basis of said photometricapparatus and which, when said object field is categorized as being insaid second condition, causes said flash controller to allow apreliminary emission by said flash apparatus and executes weightingprocess for the outputs of said segmented light adjusting elements onthe basis of the result therefrom.

In the present invention, the object field is categorized by a fieldcategorization apparatus according to its detected luminance conditionand, when the object field is categorized as being highly luminous(first condition), a region of the object field at which a highluminance exists is extracted from photometry of the steady light sothat such a region may be cut out or assigned with a lower weightingvalue. Thus a TTL light adjusting operation for an appropriate emissionmay be achieved by the controller.

Further, although the photometry of a preliminary emission in a brightscene is difficult in terms of amount of light because the aperture issmaller at the time of photographing and the ratio of the flash to thesteady light also decreases, problems in a bright scene may be solvedwithout executing a preliminary emission by using the system asdescribed above.

When the object field is categorized as being dark (second condition) bythe field categorization apparatus, a preliminary emission is carriedout by the flash apparatus and the reflected light is metered to detectthe reflection rate distribution of the object field. And, since regionsof the object field which are considered to have an adverse effect tothe TTL light adjusting operation are extracted and such regions are cutout or treated with lower weight at the time of the light adjustingoperation for the main emission, the TTL light adjusting operationcapable of an appropriate emission control may be achieved also in thiscase by the flash controller.

Since, in this manner, the camera automatically categorizes the objectfield by the field categorization means so as to automatically decidewhether a preliminary emission is to be effected, the automaticchangeover of the weighting method between a steady light system and apreliminary emission system is possible at the time of light adjustingso that an appropriate flash emission may be effected to all theregions, from a bright region to a dark region.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a conventional example and illustrating thediffusion angle of reflected light to be received by photometricelements;

FIG. 2 is a view illustrating an example of conventional light adjustingsystem;

FIG. 3 is a view illustrating a segmented light adjusting system;

FIG. 4 is a cross section of a TTL auto light adjusting camera;

FIG. 5A is a perspective view showing the overall configuration of thephotometric apparatus according to the first embodiment of the presentinvention;

FIG. 5B is a perspective showing a modification of the first embodiment;

FIG. 6 is a cross section of a camera;

FIG. 7 and FIG. 8 are front views showing the arrangement of photometriclenses and photometric elements, respectively;

FIG. 9 is a view illustrating the diffusion angle of the reflected lightto be received by the photometric elements;

FIG. 10 is a graphic presentation showing the intensity of the lightwith respect to the diffusion angle;

FIGS. 11A and 11B are views illustrating the angle of the light incidenton the photometric lens where FIG. 11A shows a photometric apparatusaccording to the present invention and FIG. 11B shows a conventionalphotometric apparatus;

FIGS. 12A and 12B are front views respectively showing variations ofarrangement for the photometric elements and for the photometric lenses;

FIGS. 13˜17 are views illustrating the second embodiment of the presentinvention, wherein FIG. 13 is a cross section of a camera showing thedisposition of the photometric element according to the presentinvention, FIG. 14A is a front view of the photometric element,

FIG. 14B is a side view of the same as seen from the right side,

FIG. 15 is perspective view showing the mounting condition of thephotometric element,

FIG. 16 is a view illustrating the advantage in the case of notproviding lead frames at the bottom end of the package, and

FIG. 17 is a front view of the photometric elements showing amodification;

FIGS. 18˜20 are diagrams showing the third embodiment of the presentinvention, wherein

FIG. 18 is a flowchart showing the light adjusting control sequence ofan auto light adjusting control apparatus,

FIG. 19 is a block diagram of the auto light adjusting controlapparatus, and

FIG. 20 is a flowchart showing the preliminary flash sequence of theauto light adjusting control apparatus;

FIGS. 21˜26 are views showing the third embodiment of the presentinvention, wherein

FIG. 21 is a perspective view showing the photometric optical system ofan auto light adjusting control apparatus,

FIG. 22 is a front view of the apparatus shown in FIG. 21,

FIG. 23 is a circuit diagram of the auto light adjusting control device,

FIG. 24 is a flowchart corresponding to the above circuit diagram,

FIG. 25 is a timing chart corresponding to the same circuit diagram, and

FIG. 26 is a circuit diagram showing in detail a portion of the circuitdiagram shown in FIG. 23;

FIG. 27 is a block diagram of an auto light adjusting control apparatusaccording to the fourth embodiment of the present invention;

FIG. 28 is an explanatory block diagram,

FIGS. 29˜33 are views illustrating the fifth embodiment of the presentinvention, wherein

FIG. 29 is a block diagram showing the overall configuration,

FIG. 30 is a diagram showing in detail the weighting light adjustmentcircuit, and

FIG. 31˜33 are flowcharts showing the processing procedure;

FIG. 34 is a block diagram of a camera according to the presentinvention;

FIG. 35 is a flowchart explaining the algorithm to be carried out in thefield categorization apparatus as shown in FIG. 34;

FIG. 36 and FIG. 37 are flowcharts explaining the algorithm to becarried out in the calculator as shown in FIG. 34;

FIG. 38 is a circuit diagram showing in detail the weighting lightadjustment circuit as shown in FIG. 34; and

FIG. 39 is a view showing examples of element pattern combination of theprimary and secondary light meters.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description will now be given by way of FIGS. 5˜12 with respect to anembodiment in which the present invention is applied to a lightadjusting device of an electronic flash apparatus.

FIG. 6 is a cross section of a camera; a portion of the object lighthaving passed through a photographing lens, not shown, is reflected by amain mirror 10 disposed in a mirror box MB and may be observed at anocular 13 via a screen 11 and a pentagonal prism 12 which comprise afinder optical system. On the other hand, the object light passedthrough the main mirror 10 is reflected at a submirror 33 and isdirected to a focus detection sensor 34 where the focus controllingstate of the object body is detected. Numeral 35 denotes a lens drivingmechanism for bringing the photographing lens to a focus.

When photographing operation is performed by using an electronic flashapparatus (not shown), the main mirror 10 is retracted as shown by thedouble-dashed line from the optical axis of the photographing lens, andthe object light having passed through the photographing lens reachesthe film surface FI for the exposure. Further, the object lightreflected at the film surface FI is directed to a light adjustingphotometric apparatus 30 which is disposed at the lower portion of themirror box MB.

This photometric apparatus 30 has a configuration as shown in FIG. 5A.

Referring to FIG. 5A, in a camera of the present invention, the imageplane is segmented into five regions (photometric regions) andphotometry is to be carried out for each of the regions; numeral 6denotes an exposure region of the film FI corresponding to a piece ofphotograph while each of 6a˜6e denotes a reflection region within thisexposure region 6, and the light from each of the photometric regions isrespectively reflected at the reflection regions 6a˜6e. As shown in FIG.7, a photometric lens 19 is a bond lens integrally retaining fiveindividual photometric lenses 19a˜19e correspondingly to the reflectionregions 16a˜16e on the film surface FI, and these photometric lenses19a˜19e are arranged in parallel and transversely to the camera.

Furthermore, on a photometric element retaining member 18, photometricelements 18a˜18e which are in the same shapes as the reflection regions6a˜6e, respectively, are retained in parallel transversely to thecamera.

A camera such as of the present embodiment which carries out an autofocusing control has only a small empty space inside the mirror boxbecause of the fact that the focus detection sensor 34 and the lensdriving mechanism 35 are located below the mirror box MB as shown inFIG. 6. By arranging both the photometric lenses 19a˜19e and thephotometric elements 18a˜18e in parallel and transversely to the camera,an increase in the size of the camera may be prevented without requiringa large disposition space even within the narrow interior of the mirrorbox MB.

Thus the light reflected at each of the reflection regions 6a˜6e isreceived by the photometric elements 18a˜18e, respectively, viaphotometric lenses 19a˜19e, and at the same time the incidence of thereflected light from other reflection regions on each of the photometricelements is restricted by effect of these photometric lenses 19a˜19e.

FIG. 9 is a view as seen from the top of the camera showing thepositional relationship among the photometric lenses 19a˜19e,photometric elements 18a˜18e and the film surface FI. l1 denotes theobject light incident on the reflection region 6d, l2 denotes lightregularly reflected thereat, and l3 denotes irregularly reflected lightwhich is incident on the photometric element 18d. With thisconfiguration, it can be seen that the aforementioned diffusion angle θbecomes θ2 which is smaller than the conventional θ1 (see FIG. 1).

FIG. 10 shows how the intensity of the light incident on the photometricelement 18 is changed with the diffusion angle θ. According to this,while the intensity e1 is weak when the diffusion angle θ is large asindicated by θ1 which is the case in a conventional art, the intensitye2 of the present embodiment is more intensified than the conventionalart because the diffusion angle θ is smaller as indicated by θ2. Thusthe amount of the light incident on the photometric element 18d isincreased and the photometry (light adjusting) may be carried out with acertainty.

Further, since the incidence of the reflected light on each of thephotometric element from other reflection regions is restricted becauseof the photometric lenses 19a˜19e, there is no overlap betweenneighboring photometric elements so that a segmented photometry may bepossible with high accuracy. Furthermore, as shown in FIG. 11A, sincethe angle φ by which the reflected light is incident on the photometriclenses 19a˜19e from the reflection regions 16a˜16e is smaller comparedto the case of using a single photometric lens as in a conventional art(FIG. 11B), there is also an advantage that the aberration is smaller,improving the image forming ability.

In addition, in the present invention, since the photometric elements18a˜18e and photometric lenses 19a˜19e are respectively retained as anintegrated body, it is not necessary to position them individually andthus it is possible to improve the efficiency of the positioningoperation.

Note that, although the photometric elements 18a˜18e and the photometriclenses 19a˜19e in the example as shown above are respectively arrangedin parallel on a straight line, they need not be arranged on a straightline. Furthermore, while an example has been shown in which thephotometric elements 18a˜18e and photometric lenses 19a˜19e correspondto each other on a one-to-one basis, it is also possible to have aconfiguration in which photometric elements 18a˜18e and the photometriclenses 36a˜36c are arranged for example as shown in FIGS. 12A and 12B sothat the reflected light from the reflection regions 6a,6b is directedto the photometric elements 18a,18b through the photometric lens 36awhile the reflected lights from the reflection regions 6d, 6e isdirected to the photometric elements 18d, 18e through the photometriclens 36b.

Moreover, the photometric lenses and the photometric elements may beretained on separate members, and in addition the segmentingconfiguration and the number of segments of the image plane are notlimited to those described above.

Still further, although the photometric elements and the photometriclenses in the embodiment as described above are arranged in parallel andtransversely to the camera at the lower portion of the mirror box MB, itis also possible as shown in FIG. 5B to arrange a photometric elementretaining member 180 and the photometric lenses 190 in parallel andvertically to the camera along the side wall of the camera within themirror box MB. Still furthermore, while the description has been givenwith respect to a light adjusting device which carries out the lightadjusting of the electronic flash apparatus on the basis of the lightreflected at the film surface, the present invention may also be appliedto an ordinary photometric apparatus which carries out the exposurecontrol by receiving the light reflected at the shutter surface.

According to the present invention, a plurality of photometric elementsare disposed in parallel in a predetermined direction so as torespectively receive the reflected light reflected with less than apredetermined diffusion angle at respective reflection regions of thefilm surface or of the shutter surface, and a plurality of photometriclenses are arranged in parallel in the above described predetermineddirection correspondingly to the plurality photometric elements. Sinceincidence on each photometric element of reflected light from otherregions is thereby restricted, photometric elements corresponding toperipheral photometric regions are also stricken by reflected light withsmaller diffusion angles, in which case the quantity of incidence can beincreased. Photometry (light adjusting) is thus possible with acertainty without increasing the size of a camera.

Furthermore, because of the above described restriction on incidencefrom other reflection regions, there are no overlaps among theneighboring photometric regions and a plurally segmented photometrybecomes possible with high accuracy. In addition, since the angles ofincidence on the photometric lenses from each of the reflection regionson the film surface or on the shutter surface become smaller compared toa case of using a single photometric lens such as in a conventionalconfiguration, there is another advantage that the image forming abilityis increased due to a smaller aberration.

A second embodiment of the present invention will now be described withreference to FIG. 13˜FIG. 17.

FIG. 13 is a cross section of a camera. A portion of the object light,having passed through the photographing lens LE and being directed intothe interior of the camera body 9, is reflected at a main mirror 10 andis directed to an ocular, not shown, through a screen 11 and apentagonal prism 12 which constitute a finder optical system. On theother hand, another portion of said object light is reflected at asubmirror 33 after passing through the main mirror 10 and is directed toan AF sensor module 20 through a hole 37a of a substrate 37 (see FIG.15) which is fixed within the interior of the camera body 9. In thisconfiguration, the AF sensor module 20 is retained at the bottom of thecamera body in a suspended condition from said substrate 37 via columns38. Thus a known focus detection operation is carried out on the basisof the incident object light.

Further at the time of photographing using an electronic flashapparatus, not shown, the illuminating light of the flash apparatus,after being reflected at the object, is directed into the interior ofthe camera body 9 through the photographing lens LE. At this time, sincethe main mirror 10 and the submirror 33 are integrally retracted fromthe optical path of the photographing lens LE, the incident light isdirected to the film located at the rear portion of the camera body 9and is reflected at the film surface FI. And some of the irregularlyreflected light thereat is incident on photometric element 21 viaphotometric lens 36 fixed with an inclination on a fixed portion 9a ofthe camera body 9 and via a filter 39.

FIG. 14A is a front view of the photometric element 21, and FIG. 14B isa side view from the right side of the same. A transparent plastic moldpackage (body) 22 in a rectangular shape is cut at its upper and lowerends and at its left and right (the transverse direction of the camera)ends so as to form mountain-shaped ends thereat, and at the interior ofwhich light receiving portions 21a˜21e and a circuit portion (not shown)in a form of IC are provided. As has been described with reference tothe conventional art, the light receiving portions 21a˜21e are designedto respectively receive the reflected light from five regions 6a˜6e(FIG. 3) of the film surface FI and are respectively fixed at positionsdisplaced downward from the center of the package 22 as shown in thefigure.

Further, a plurality of lead frames 23 are respectively projected fromthe upper end portion and the left end portion of the package 22, andtheir distal ends are bent so as to be in the same plane as a surface22a of the package 22 as shown in FIG. 14B. Furthermore, lead frames 40,41 for the fixing and positioning are projected from the left and rightend portions of the package 22 at positions displaced upwardly from thecenter of the package 22, and a fork-like portion 40a is provided at thelead frame 40 while a bored portion 41a is formed at the distal end ofthe lead frame 41.

Referring to FIG. 13, a pair of extended portions 36a (only one beingshown) are formed on the above described photometric lens 36 at bothends thereof that are transverse to the camera and each of the extendedportions 36a is formed with a boss 42 which protrudes obliquelyfrontward therefrom. The photometric element 21 is inserted into awindow portion 37b of the substrate 37 as shown in FIG. 15, and thefork-like portion 40a of the lead frame 40 is caused to engage one ofthe above described bosses 42 while the bored portion 41a of the leadframe 41 engages with the other boss (not shown). Package 22 is therebyretained at the upper portion of the AF sensor module 20 with aninclination with respect to the film surface FI.

Thus, the object light reflected respectively at the regions 6a˜6e (FIG.3) of the film surface FI, after passing through the photometric lens 36and the filter 39, is respectively received by the light receivingportions 21a˜21e through the plastic package 22. At the circuit portionin the package 22, electrical signals in accordance with the amount ofthe light received at the light receiving portions 21a˜21e are inputtedinto a light adjusting circuit, not shown, and the light adjustingcircuit integrates the inputted current and, when the integrated amountreaches a predetermined amount, outputs an emission stop signal to stopthe emission of the electronic flash apparatus.

Since the lower end portion of the package 22 is cut into amountain-like configuration, its lowermost surface 22b is generallyparallel to the upper surface 20a of the AF sensor module 20, and, sincein addition the signal transmitting lead frames 23 are not projectedfrom the lower portion of the package 22, the package 22 may be placedimmediately above the the AF sensor module 20 as shown in the figures.Extent of the protrusion of the package 22 in the vertical direction isthereby held to the minimum, and the size of the camera body 9 mayaccordingly be reduced in its vertical direction.

Further, according to the present invention, there is also an advantageas follows.

Since, as shown in FIG. 15, the window 37b of the substrate 37 is notallowed to exceed a limit in size because of the requirement instrength, the photometric element 21 cannot be retained within thewindow 37b if lead frames 23 are to be protruded from the left and rightend portions thereof (both ends in the transverse direction of thecamera). In the present embodiment, however, because of the fact thatthe signal transmitting lead frames 23 protrude respectively from theupper and left end portions (only one of the ends in the transversedirection of the camera), it is possible to retain the whole of thephotometric element 21 within the window 37b without reducing the numberof lead frames 23.

Furthermore, as shown in FIG. 16, since the package 22 is disposed withan inclination and also since the distal ends of the lead frames 23 arebent, the extent H3 in the vertical direction is larger when the leadframes 23 are extended from the lower portion of the package 22 as shownby the double-dashed line. When the lead frames 23 are extended from theupper portion of the package 22 as is the case in the presentembodiment, the vertical extent may be reduced such as to H2.

Still further, since a pair of fixing lead frames 40, 41 are extendedfrom the both ends transverse to the camera of the package 22 atpositions displaced from the center thereof, the fixing lead frames40,41 may be accurately positioned and fixed without abutting the edgeof the window 37b.

Still further, since the light receiving portions 21a˜21e arerespectively secured to positions displaced downward from the center ofthe package 22, the extent of the upward protrusion of the photometriclens 36 may be reduced and there is no partial incidence of regularlyreflected light from the film surface FI upon the light receivingportions 21a˜21e. An accurate light adjusting result may thus beobtainable.

Note that the positions from which the lead frames 23 are extended arenot limited to those of the embodiment and as shown in FIG. 17 forexample they may be extended from all the end portions but the lower endof the package 22.

Moreover, though a case with an AF sensor module has been shown, if theAF sensor module 20 is not provided, the package 22 may be placed sothat its lower end surface is generally parallel to the bottom surfaceof the camera body 9. Further, while there is a camera known to performa pre-emission before the flash photographing to check the reflectionrate of the object, the luminous flux reflected at the shutter blindsurface instead of the film surface FI is measured if such apre-emission is to be effected.

In addition, while an example has been shown in which the film surfaceis segmented into five segments, the number of segments is not limitedto this. Or the present invention may be applied even to thoseperforming a usual light adjusting without such a segmentation, i.e., tothose with a single light receiving portion. Further, the application ofthe present invention is not limited to the light adjusting of anelectronic flash apparatus and it may also be applied in a similarmanner to an ordinary photometric element used in an exposure control.In such a case, the photometry is also carried out on the basis of thelight reflected at the shutter blind surface.

According to the present invention, the lower end surface of thephotometric element body is placed generally parallel to the bottomsurface of the camera body or to the upper surface of the AF sensormodule and the signal transmitting lead frames are extended fromportions other than the lower portion of said body. The disposing spaceof the photometric element may thus be reduced within the camera body,and an increase in the size of the camera is restricted to the minimumeven when the number of the light receiving portions is increased inemploying a segmented light adjusting system as described above.

Furthermore, even when the AF sensor module is disposed at the bottom ofthe camera body, the coexistence of the AF sensor module and thephotometric elements as described above is possible while restricting tominimum an increase in the size of the camera.

FIG. 21˜FIG. 26 show a third embodiment of the present invention.

First, a configuration of the light receiving optical system isdescribed with reference to FIG. 21 and 22.

FIG. 21 is a view showing the structure of the photometric element 7 andthe photometric lens 8. The photometric element 7 includes on the sameplane a segmented photometric element 7c which corresponds to a circularphotometric region and segmented photometric elements 7e, 7d, 7b, 7a atboth sides thereof each of which corresponds to a photometric region inthe shape of a rectangle cut by an arc. The photometric lens 8 is anoptical member having at positions thereabove three lens portions 8a,8b, 8c corresponding to the three blocks in the photometric regions.

FIG. 22 is a view showing the optical relationship among the openedregion 6 of the film surface, the photometric element 7 and thephotometric lens 8 as seen from the direction of A in FIG. 4. The openedregion 6 of the film surface is segmented into five regions, a centralcircular portion 6c and four regions 6b, 6c, 6d, 6e segmenting theperiphery thereof. The three, center, left and right, blocks consistingof the five photometric regions of the photometric element as shown inFIG. 21 supervise respectively the center, left half and right half ofthe film surface opened portion via the three lens portions of thephotometric lens as shown by the broken line, the dashed line and thedouble-dashed line, respectively, and images are almost formed thereon.Furthermore, since the five segmented photometric elements 7a˜7e of thephotometric element 7 as shown in FIG. 21 are caused to correspond inshape to the regions 6a˜6e of the film surface opened regions as shownin FIG. 22, the luminosity values of the five regions are separatelymetered.

FIG. 23 is a view showing the circuit configuration of the presentinvention.

This figure comprises the camera body 9 and the flash apparatus 16, andthey are electrically coupled to each other by means of contacts T1, T2,T3 and T11, T12, T13.

The flash apparatus 16 controls the starting and stopping of the flashof the emitting portion upon the reception by the emission controlcircuit 29 of an emission start signal from the contact T12 and anemission stop signal from the contact T11. Contact T13 is a contact totransmit the GND electric potential.

The configuration of the camera body 9 is as follows.

The photometric elements 7a˜7e are segmented into five regions as shownin FIG. 21, and each of which provides an electrical signal inaccordance with the luminous intensity. Amplifiers 44a˜44e are means forrespectively amplifying the output of the photometric elements 7a˜7e,and the respective amplification factor may be independently andvariably set in accordance with output of gain setting signal outputmeans 45˜49. These gain setting means correspond to a block 28a of aweighted light adjusting circuit 28 in FIG. 19. The gain setting signaloutput means 45˜49 includes a D/A converter which converts a digitalsignal from a microcomputer 50 into an analog electrical signal. Theoutputs of the amplifiers 44a˜44e are branched into two systems, and oneof the systems enters into integration means 51˜55 respectively for eachoutput. The integration means 51˜55 integrates the outputs of theamplifiers 44a˜44e respectively or resets the integrated amount on thebasis time interval in accordance with a single integration controlsignal ITGpre provided by the microcomputer. The outputs of theintegration means 51˜55 are inputted into conversion input terminals A/D1˜5 of the microcomputer 50. Another branch of the outputs of theamplifiers 44a˜44e enters into adding means 56 and the five output areadded thereat. Its output is integrated on the basis of time intervalsor a resetting of the integrated amount is carried out at theintegration means 57 in accordance with an integration control signalITG provided by the microcomputer 50. The output of the integrationmeans 57 is compared with the output of a criterion level generationmeans 59 at a comparator means 58, and the result is entered into one ofthe input terminals of an AND gate 60. One of the output ports of themicrocomputer 50 enters into the other input terminal of the AND gate60, and the output terminal of the AND gate 60 is connected to thecontact T1. Block 28b of the weighted light adjusting circuit 28 asshown in FIG. 19 comprises the adding means 56, the integration means57, the criterion level generation means 59, the comparator means 58 andthe AND gate 60.

A switch 61 is turned on from off when the mirror up operation iscompleted in the sequence of the camera and is returned to its off stateupon the start of the mirror down operation, and its output is enteredinto one of the input ports of the microcomputer 50. A switch 62 isturned on from off when the shutter is fully opened upon the completionof opening of the leading curtain of the shutter and is returned to itsoff state with the shutter charge operation after the complete closingof the trailing curtain of the shutter, and its output enters one of theoutput ports of the microcomputer 50. Numeral 63 denotes an interfacefor outputting a signal which upon the receipt of the output from themicrocomputer 50 informs the flash apparatus 16 via the contact T2 ofthe timing of starting the emission. Numeral 64 is an interface forcontrolling the electric conduction of a magnet 65 which retains theleading curtain upon the receipt of an output from the microcomputer 50,and numeral 66 is an interface for controlling the electric conductionof a magnet 67 which retains the trailing curtain in a similar manner.

The operation of the block as shown in FIG. 23 of the present embodimentwill be described in accordance with the flowchart in FIG. 24 and withreference to the timing chart in FIG. 25.

Referring to FIG. 24, at step S30, the program waits for an operation ofa release start-up means, not shown. When it is operated and the releaseoperation is started, the shutter magnets 65, 67 are supplied byelectricity at step S31 and the leading curtain and the trailing curtainare retained by means of the electricity, and at the same time themirror up operation is started by starting a mirror driving means (point"a" in FIG. 25), not shown. The program waits at step S33 for turning onof a mirror up operation completion detecting switch 61, and, when it isturned on (point "b" in FIG. 25), the program proceeds to step S33 wherea signal is outputted so that signals at an identical level are providedby gain setting signal output means 45˜49, i.e., so that theamplification factors of the five amplifiers 44a˜44e are setidentically.

This is a preparation so that outputs may be read by using a same scalewhen the reflection rate distribution of the segmented object field dueto a flash emission is detected on the basis of a preliminary flashwhich is to be carried out immediately thereafter. Further, the set gainin this case is preferably set at a high level so as to earn more than acertain degree of integrated output even if the preliminary emissionquantity is small. After waiting for 10 msec at step S34 which isnecessary to quiet the mirror bound, the contact T2 is lowered to itslow level so as to cause the flash apparatus 16 emit a preliminary flashat step S35 while both of the integration signals ITGpre and ITG arelowered to their low level (point "c" in FIG. 25). When the flashapparatus 16 receives the emission start signal from the contact 12, theemitting portion 43 is started to emit by the action of the flashcontrol means 29. Then as shown in the timing chart in FIG. 25, with therising of the flash wave form, outputs respectively integratingelectrical signals corresponding to the reflected lights from theshutter leading curtain surface, which correspond to the segmentedregions at the opened film surface portion, rise from "c" to "d" asindicated by the curves of 51˜55 integrated outputs.

At the same time, the outputs of the amplifiers 44a˜44e are added bymeans of the adder 56 so that the output voltage integrated at theintegration means 57 also rises from point "c" to point "d". Although alow level signal is supplied to the AND gate 60 when the criterion levelis exceeded by at the comparator means 58, the microcomputer 50 at stepS36 outputs a signal to the AND gate 60 at 100 μsec after the outputtingof the emission start signal (point "d" in FIG. 25) even when thecriterion level is not reached so as to bring the contact T1 to its lowlevel. This is a signal to instruct the flash apparatus 16 to stop theemission and means to restrict the maximum limit of the emitted amountin preparing for the main flash even when the received light amount isfound to be insufficient as a result of the light adjusting, though thelight adjusting is effected also at the time of preliminary flash. Thusthe flash apparatus 16 is caused to instantly stop the emission of theemitting portion 43 by the action of the flash control means 29, and,after the point "d" in FIG. 25, each integrated output is in fact fixed.

At this interval, the microcomputer 50 at step S37 serially carries outA/D conversion with respect to five input levels at the A/D conversioninput terminals and stores the results. In other words, at this point,the segmented reflection rate distribution on the basis of thepreliminary flash by the flash apparatus 16 is detected.

When all A/D conversions are completed, all of the contacts T2,T1 andthe integration control signal ITGpre are returned to their high level(point "e" in FIG. 25). When ITGpre is returned to its high level, theintegrated amount at the integration means 51˜55 are reset.

Then, at step S39, a predetermined calculation is performed in themicrocomputer 50 in accordance with the flowchart as shown in FIG. 20 bymeans of weighting calculation means 26, as described above, shown inFIG. 19 on the basis of the five integrated outputs so as to determinethe weights to be applied at the subsequent main flash to the outputs ofthe five photometric elements 7a˜7e. At step S40, signals are suppliedto the gain setting signal output means 45˜49 to apply gainscorresponding to thus determined weights respectively to the amplifiers44a˜44e. After its completion, at step S41, the electric conduction ofthe leading curtain magnet 65 is terminated so as to start running ofthe leading curtain and the system waits at step S42 for the turning onof the switch 62. When this is turned on, i.e., the shutter is fullyopened (point "f" in FIG. 25), the system proceeds to step S43 where asignal is outputted to the interface 63 so as to bring the contact T2 tothe flash apparatus 16 to its low level, whereby, while causing to startthe emission of the flash apparatus 16, the integration control signalITG at its low level is outputted to the integration means 57 (point "g" in FIG. 25).

The light adjusting control from this point on leaves the microcomputerprogram and is carried out by the hardware as shown in FIG. 23. Whenreceiving the emission start signal from the contact T12, the flashapparatus 16 is caused to start an emission of the emitting portion 43by the action of the flash control means 29 in the similar manner as theprevious preliminary flash of the flash apparatus 16. As shown in thetiming chart in FIG. 25, with the rising of the emission wave form, anintegrated output voltage, which has been integrated by the integrationmeans 57 through the addition at the adder 56 of the outputs, providedby the amplifiers 44a˜44e to which gains have been respectively appliedin accordance with the previously obtained weights, based on theelectrical signals corresponding to the reflected lights from the filmsurface which correspond to the segmented regions on the opened portionof the film surface, rises from point "g" to point "h". Comparator means58 provides a low level output when the criterion level 59 is exceededby the output of the integration means 57 (point "h" in FIG. 25). Thisoutput is transmitted from the contact T1 to the flash apparatus 16 viathe AND gate 60 as a signal for stopping the emission. The flashapparatus 16 instantly stops the emission of the emitting portion 43 bythe action of the flash control means 29 so as to complete the lightadjusting.

Afterwards, it is returned to the control by the microcomputer 50 thatthe shutter time is measured at step S44, and the electric conduction ofthe trailing curtain magnet is removed at step S45 so that running ofthe trailing curtain is started (point "i" in FIG. 25). A 10 msec delayis provided at step S46 to wait for the completion of the trailingcurtain run, and the contact T2 and the integration control signal ITGare returned to their high level at step S47 (point "j" in FIG. 25).

At steps S48 and S49, in preparing for the next shutter release, ashutter charge, mirror down (point "k" in FIG. 25) and film winding areeffected by means which are not shown, and the program then returns tostep S30.

Through the description as above, steps S35 to S40 in the flowchart mustbe performed between the completion of the mirror up and the point atwhich the leading curtain is started to open, and such a time intervalaccordingly causes an increase in the time lag for the shutter release.However, the time required for this may be estimated as 100 μsec at themaximum for the preliminary flash, 3 msec at most for the A/D conversionof the five integrated outputs and about 2 msec (depending on theprocessing speed of the microcomputer) for the calculation of theweights for the main flash from thus obtained result. Thus there is onlyan about 5 msec increase in time comparing to a prior system and asubstantial delay is not caused.

A circuit diagram for the weighted light adjusting circuit 28 will nowbe described further in detail with reference to FIG. 26.

The photometric elements 7a˜7e are constituted by five photodiodes, and,when these photometric elements are stricken by light, electricpotentials corresponding to the quantities thereat are outputted fromOP-amps 835a˜835e and are applied to the bases of the transistors837a˜837e. While collector currents then flow in from the Vcc viacondenser Cn, the amounts thereof vary according to the electricpotentials at the variable power sources 838a˜838e. The amplifiers44a˜44e as shown in FIG. 23 are constituted by the OP-amps 835a˜835e,the transistors 837a˜837e and the variable power sources 838a˜838e.

Electric potentials at these variable power sources 838a˜838e are set asthe result that voltages En outputted from the output portion POA-E ofthe CPU 50 of the weight calculation means 26 as described above are setvia the A/D converters 823b˜823f.

For example, when supposing that the portion corresponding to asegmental photometric element 7a of the photometric element 7 hasreceived little reflected light of a preliminary flash and thus areflection rate distribution of R1=0.05 has been detected, the assignedweight becomes D1=0 and a large value is set as the voltage E1 from theaforementioned formula (3), En=K(1-Dn)Er. Then, the collector currentflowing into the transistor 837a becomes smaller and thus is not likelyto contribute to the cumulation of the electric charge at the condenserCn. A comparator 842 is designed to provide an emission stop signal tothe flash control apparatus 29 when the criterion potential Ek at anonreversible input terminal side is exceeded by the potential at areversible input terminal side. The fact of making little contributionto the charge cumulation at the condenser Cn (corresponding to 56,57 asshown in FIG. 23) thus means that a low weight has been assigned to theoutput of the photodiode 7a and that an effect from the portion whichadversely affects the TTL light adjusting has been removed.

As shown in the figure, a circuit identical to one comprising 834a˜838ais attached to each of the photodiodes 7b˜7e, and the circuits arerespectively integrated with the collectors of the transistors 837a˜837eand are connected to the condenser Cn. Thus the output of a photodiodein a photometric region to which a high weight is assigned is morelikely to contribute to the charge cumulation at the condenser Cn andpredominantly determines the output timing of the emission stop signal.

FIG. 27 is a block diagram of a fourth embodiment according to thepresent invention. Referring to FIG. 27, those components which areidentical in function to those shown in FIG. 19 are denoted by the samenumerals and detailed descriptions therefor are omitted.

The characteristic of the fourth embodiment as shown in FIG. 27 and FIG.4 is such that photometric element 15 for the reflected light of apreliminary flash and photometric element 7 for the reflected light ofthe main flash are separately provided.

When the main mirror 10 is down to the position as indicated by thebroken line in FIG. 4, the light passing through the photographing lensgroup LE is reflected at the main mirror 10 and is further reflected atthe pentagonal prism 12, and a portion of which reaches the photometricelement 15 through the photometric lens 14. The photometric element 15is segmented as shown in FIG. 27 and is designed to meter the reachinglight, and its output is transmitted to the weighting factor calculationmeans 26 to be subjected to the calculation.

In the operation, when the release button is released at a condition asshown in FIG. 4, a preliminary flash by the flash apparatus 16 isperformed, and the light reflected by the object passes through thephotographing lens group LE, is reflected by the main mirror 10 which isat the position indicated by the broken line and is received by thephotometric element 15 via the photometric lens 14.

The photometric element 15 comprises segmented photometric elements15a˜15e which are obtained by segmenting into five regions in the samemanner as the photometric element 7. This photometric element 15 carriesout photometry by segmenting the object field into five regions, andthus obtained photometric currents are inputted into the weightingamount calculation means 26 so that the detection of the reflected lightfrom the object field may be carried out through steps S14˜S23 as shownin FIG. 20.

Weighting factors are then determined by the weighting factorcalculation means 26 on the basis of the output from the photometricelement 15 and are entered into the weighting light adjustment circuit28. Next, the main mirror 10 is up and at the same time the aperture 25of the lens is reduced to achieve the photographing aperture value,whereby a main flash of the flash apparatus 16 is performed. At thistime, the reflected light of the main flash returned from the object isreflected at the film surface FI so as to be measured in segments by thephotometric element 7, and thus obtained photometric outputs aresubjected to weighting at the light adjusting circuit 28 and are thenintegrated. And, when this integrated value reaches a predeterminedvalue, the emission of the flash apparatus 16 is stopped by the flashcontrol means 29.

Note that the weighting calculation on the basis of a preliminary flashcaused by the flash apparatus 16 is only required to determine therelative weighting factors for the segmented regions, whereby thepreliminary flash may be shorter in time than a main flash, makingunnecessary a large capacity electric power source.

As described above, according to the present invention, an effectivephotometric system, in which the object field is segmented to obtain aluminance information from which a most suitable exposure for the mainobject is obtained through a predetermined algorithm, may also beapplied to a flash photographing, and a photograph with an appropriateexposure can be taken even at a scene where a large discrepancy inexposure occurs when using a conventional TTL auto light adjustingcontrol system.

Further, since using a preliminary flash means emitting twice, therehave been complaints when the subject is a person such as that thepreliminary flash is dazzling or that a photograph with closed eyes isresulted. However, since, in the present invention, a preliminary flash,detection of reflection rate and calculation of weighting factors arecarried out at a high speed immediately before the opening of theshutter, only a few msec is required as the time interval between thepreliminary flash and the main flash, it is not sensed that there havebeen two emissions and a better impression is provided even when thesubject is a person.

Furthermore, since the delay in opening of the shutter after the mirrorup is only a few msec when using a single-lens reflex camera, there isalso an advantage that little changes occur in the so-called time lag orin the release feeling.

Still further, according to the present invention, a configuration asshown by the embodiment becomes possible in which the leading curtainsurface of a focal plane shutter is not used as the reflecting member atthe time of preliminary flash, and thus the present invention may alsobe applied to cases where another curtain is prepared to have variousconfigurations and various reflection rate distribution.

Still further, according to the present invention, on the basis of thereflected light obtained from a preliminary flash, the regions whichadversely affects the light adjusting control, such as a region at whichthe reflection rate becomes very high for example because of agold-leafed folding screen existing in the object field or a region atwhich the reflection rate becomes very low because its object field is abackground, are ignored and removed from the subject of weightingdecision. Thus the light adjusting at the time of main flash may beaccurately carried out.

A description will now be given by way of FIGS. 29˜33 with respect to afifth embodiment in which the present invention is applied to asingle-lens reflex camera as shown in FIG. 4.

FIG. 29 is block diagram of a camera according to the present invention.An exposure calculating photometric element 15 is segmented into fiveregions 15a˜15e and carries out photometry by segmenting the objectfield into five regions. The five outputs of this exposure calculatingphotometric element are entered into a microcomputer 69 having such as aCPU 69A and an A/D converter 69B and are used in a known exposure valuecalculation. Further, a light adjusting photometric element 7 is alsosegmented into five regions 7a˜7e and carries out photometry bysegmenting the object field into five regions at the time of flashphotographing. The object field segmented by these five regionscorresponds to the object field segmented by the five regions of theexposure calculating photometric element 15. Five outputs of this lightadjusting photometric element 7 are entered into the weighting lightadjusting circuit 28.

A release signal from the release button 24, an ISO information from anISO information setting circuit 27, an opened F value signal from abuilt-in memory 70 of the lens and an exposure mode information from anexposure mode setting circuit 71 are respectively inputted into themicrocomputer 69. Set as exposure modes are a program mode (P), anaperture priority mode (A), a shutter speed priority mode (T), and amanual mode (M). The microcomputer 69 calculates the aperture value andthe shutter speed by using known methods and controls the shutter 17 andthe aperture 25 via an exposure control circuit 68. It furthermoredecides whether a flash photographing is appropriate and inputs anemission start signal into the flash control apparatus 29 at apredetermined timing at the time of flash photographing. In addition,the microcomputer 69 as will be described later calculates a weightingvalue Dn from a reflection rate distribution, and Dn is converted into avoltage En by the following formula (3) to be entered into the weightedlight adjusting circuit 28.

    En=K(1-Dn)Er                                               (3)

where n is 1˜5

Er is the standard voltage, and

K is a value corresponding to the ISO information.

The weighted light adjusting circuit 28 as shown in FIG. 30 comprises:logarithmic compression circuits 72a˜72e for respectively outputting theoutputs from the regions 7a˜7e of the light adjusting photometricelement 7 in a logarithmically compressed manner; integration circuits73a˜73e for respectively integrating the outputs from the logarithmiccompression circuit 72a˜72e; weighting correction circuits 74a˜74e forassigning weights for the outputs of the logarithmic compression circuit72a˜72e; a condenser 75 for integrating the electric current flowingfrom the power supply voltage Vcc in accordance with the five outputs ofthe logarithmic compression circuit 72a˜72e to which correcting weightshave been respectively assigned; and a comparator 58 which makes acomparison between the voltage signal integrated at the condenser 75 andthe voltage signal from the criterion power source 76 and which providesan emission stop signal when the criterion voltage signal is exceeded bythe voltage signal from the condenser 75.

Logarithmic compression circuits 72a˜72e respectively comprise op-ampsOPa˜OPe and feedback diodes Da˜De and standard voltage Er.

Weighting correction circuits 74a˜74e respectively comprise transistorsTra˜Tre, variable power supply source VEa˜VEe, and the variable powersupply source VEa˜VEe are respectively set at voltage En (n=1˜5), shownby the above mentioned formula (3), provided by the microcomputer 69.The emission stop signal from the comparator 58 is inputted into theflash control circuit 29 so as to stop an emission of the flashapparatus 16.

Operation of a TTL auto light adjusting camera having a configuration asabove will now be described in accordance with the flowcharts in FIG.31˜FIG. 33.

Referring to FIG. 31, the program proceeds to step S51 when the releasebutton 24 is turned on where luminance values BVn (n=1˜5) possessed byfive outputs from the exposure calculating photometric element 15 areread, and it then proceeds to step S52 at which a decision is made onuse/nonuse of the flash apparatus 16. The program proceeds to step S53when using the flash apparatus 16 while it proceeds to step S60 when notusing the same.

At step S53, the exposure value BV is determined by processing theluminance values BVn with a predetermined algorithm (see for exampleFIG. 5 of Japanese Patent Laid-Open No. 63-83713). ISO information andexposure value are read at step S54 and the program then proceeds tostep S55 at which it is seen if a programmed mode is used. When theprogram mode is used, at steps S56,S57, if the demanded aperture valueAV exceeds a predetermined aperture value AVx, the value is limited toAVx, and the program then proceeds to step S58.

At step S58, shutter speed TV and aperture value AV are determined onthe basis of the exposure value BV determined at step S53, the ISOinformation and the exposure mode. At step S59, a comparison is madebetween the aperture value AV determined at step S58 and thepredetermined aperture value AVx. If AV>AVx, the program proceeds tostep S71 in FIG. 32 while, if AV≦AVx, the program proceeds step S81 inFIG. 33. An aperture value AVx takes a value such as f=5.6, and, if itis further stopped down from this value, a reflection rate distributioncannot be accurately measured at the time of a preliminary flash becauseof a lack of quantity of the light reaching the light adjustingphotometric element 7 through the lens LE. Accordingly, at the procedurefollowing step S71, no preliminary flash is carried out and aphotographing is performed with a main flash after setting predeterminedweighting factors which emphasize the central portion.

FIG. 32 shows the procedure at step S71 and thereafter. At step S71, astopping down to the determined aperture value AV and a mirror up arecarried out, and, without a preliminary flash, the program proceeds tostep S72 at which weighting factors Dn are set. In this embodiment,weighting amounts Dn at the time of using a small aperture value are setwith the emphasis on the center region as follows:

the center region D1=2/6

the peripheral regions D2-D5=1/6.

Next, at step S73, voltage values En corresponding to the weightingamounts Dn are obtained from the aforementioned formula (3) and thevariable power supply sources VEa˜VEe of the weighted light adjustingcircuit 28 are set with these values by means of microcomputer 69. Atstep S74, the microcomputer 69 supplies an emission start signal to theflash control circuit 29 to cause to start a main flash while drivingthe shutter 17 with a predetermined timing. And, at step S75, a lightadjusting is carried out.

Light adjusting in this embodiment is effected as follows.

Outputs from the regions 7a˜7e of the light adjusting photometricelement 7 are amplified by means of logarithmic compression circuit72a˜72e and then inputted into the bases of the transistors Tra˜Trewhich comprise the weighting correction circuit 74a˜74e. Thereby,transistors Tra˜Tre are turned on so that a collector currents isstarted to flow from the power supply voltage Vcc via the condenser 75.Variable power sources VEa˜VEe which are respectively connected to theemitters of the transistors Tra˜Tre are respectively set at voltages Enso as to emphasize the center region, and the collector current becomeslarger with the decrease in the voltage value En. In this case,therefore, the condenser 75 is charged depending more on the photometricoutput of the center region 7c than on the peripheral regions of thephotometric element 7. When a criterion potential is exceeded by thepotential of the condenser 75, an emission stop signal from thecomparator is inputted into the flash control circuit 29 from thecomparator 58 to stop the flash.

When it is seen as AV≦AVx at step S59 in FIG. 31, i.e., if thedetermined aperture value AV is closer to the opened aperture value thanthe predetermined aperture value AVx is, the program proceeds to stepS81 as shown in FIG. 33. In procedure at step S81 and thereafter, thereflection distribution of the object field is assumed from thereflected light of a preliminary flash to be carried out, and a lightadjusting is performed by accordingly setting weighting amounts for theoutputs of the light adjusting photometric element 7.

At step S81, the mirror 10 is up and the aperture 25 is stopped down,and then at step S82 the microcomputer 69 provides a preliminary flashsignal to the flash control circuit 29 to perform a preliminary flash.The reflected light from the object body due to the preliminary flash isreflected at the shutter blind surface 17 through the photographing lensLE and reaches to the light adjusting photometric element 7 through thephotometric lens 8. As described above, the element surface of the lightadjusting photometric element 7 is segmented into five regions, and itmeters the light by segmenting the object field into five regions.Photometric outputs corresponding to the quantity of the reflected lightfrom the object body are integrated at the integration circuits 73a˜73e,and, at step S83, the integrated signals are entered into themicrocomputer 69, whereby the reflection rate distribution is calculatedby the following formula as: ##EQU3## where n=1˜5.

At steps S85 to S91, regions at which reflection rate distribution Rn(n=1˜5) is very high (Rn>0.8) and regions at which it is very low(Rn<0.1) are extracted and are cut out. Existence of photometric regionswith very high Rn means that there are behind the subject (person) forexample a gold-leafed folding screen or a white wall. Also, an existenceof photometric regions with very low Rn means for example that thebackground of the subject (person) is such as a landscape which causes akind of emptiness. In either case, these regions are cut out becausethey may be the factor adversely affecting the TTL light adjusting. Inother words, the reflection rate distributions Rn (n=1˜5) for theregions to be cut out are replaced by 0 so that they do not contributeto the subsequent calculation.

When cutting outs of both high and low luminances are completed withrespect to the whole region of the light adjusting photometric element7, the program proceeds to step S92 at which weighting amounts Dn areobtained, by using the reflection rate distributions Rn (n=1˜5) afterthe cutting out, from the following formula: ##EQU4## Then, at step S93,the weighting amounts Dn are converted into voltage values En on thebasis of the formula (3) and are entered into the weighted lightadjusting circuit 28.

Subsequently, at step S94, the microcomputer 69 causes the flashapparatus 16 to emit a main flash by supplying a an emission startsignal to the flash control circuit 29. At this time, the main mirror 10is in its mirror up state and the aperture 25 of the lens is stoppeddown to the photographing aperture value so that the reflected light ofthe main flash from the object body reaches the light adjustingphotometric element 7 through the lens LE by the route as describedabove, and the reflected light of the main flash from the object ismetered in five segments. Photometric outputs from the light adjustingphotometric element 7 are weighted at the timing of step S95 in aweighted light adjusting circuit 28 and are then integrated by thecondenser 75. And, when the integrated amount of the five regionsexceeds a criterion value, the emission stop signal is supplied from thecomparator 58 to the flash control circuit 29 to stop the emission.Therefore, if the reflection rate for the center region 7c is higherthan those for the other peripheral regions, photometric outputs of theperipheral regions contribute more to the detection of light quantitythan the photometric output of the center region. If the reflection ratedistribution for the center region 7c is higher than a predeterminedvalue or is lower than a predetermined value, the photometric output ofthat region does not contribute the detection of light quantity. As aresult, an appropriate light adjusting is possible even when for examplethe reflection rate of the object is very high.

On the other hand, if it is decided at step S52 in FIG. 31 that theflash apparatus 16 is not to be used, an exposure value BV is determinedat step S60 by using luminance value BVn in accordance with thealgorithm for an usual photographing. Then, at step S61, the ISOinformation and exposure mode are read and furthermore at step S62 theshutter speed TV and the aperture value AV are determined. Subsequently,at step S63, the mirror up and the stopping down of the aperture 25 areeffected, and, at step S64, a photographing is carried out.

In the configuration of the embodiment as above, the flash apparatus 16constitutes flash means; the light adjusting photometric element 7constitutes photometric means; the microcomputer 69 constitutesweighting amount calculation means; the condenser 75, the criterionpower source 76 and the comparator 58 of the weighted light adjustingcircuit 28 constitute light adjusting means; the microcomputer 69constitutes decision means; the microcomputer 69 and the flash controlcircuit 29 constitute flash control means; and the exposure controlcircuit 68 constitutes aperture value setting circuit.

In the embodiment as above, when a programmed exposure mode is used, aset aperture value is limited by a predetermined aperture value becauseof the following reasons. With an aperture priority mode or with amanual mode, an intended photographing effect may not be obtained if aset aperture is restricted to be larger than a predetermined aperturevalue, because a small aperture value may be intentionally set by thecamera user. Since, however, a consideration for such photographingeffect is not required with the programmed exposure mode, the aperturevalue is restricted to be larger than a predetermined value so as tocarry out more accurate light adjusting. The aperture value may also becontrolled on a programmed line figure.

Although in the above a weighting amount is calculated for each regionof the light adjusting photometric element 7 so that a photometricoutput of each region is respectively corrected, it is not necessary tocarry out weighting correction for each region. It is also possible tobring some regions into a group where a weighting amount may becalculated for each group for the correction. In either way, the methodof correction may be any method as far as the correction is to be madein accordance with the reflection rate distribution of the object field.Further, the exposure mode can be any mode, though a description hasbeen given above for a camera with four exposure modes.

According to the fifth embodiment of the present invention, weightingamounts related to the reflection rate distribution of the object fieldare calculated on the basis of photometric outputs of the lightadjusting photometric element at the time of a preliminary flash onlywhen the aperture valued is less than a predetermined aperture value,and the light adjusting photometric outputs which are corrected inaccordance with thus obtained reflection rate distribution arerespectively integrated at the time of main flash so that the flash iscaused to stop when a criterion value is exceeded by the integratedvalue. Therefore, an appropriate exposure is possible under anyphotographing condition regardless of the subject even when thephotographer intentionally sets a small aperture value. In the case ofsmall aperture, even more appropriate light adjusting is possible if thephotometric elements are corrected in accordance with a predeterminedreflection rate distribution. Furthermore, with a programmed exposuremode, an appropriate light adjusting is possible for any subject if apreliminary flash is carried out without exception by restricting theset aperture value at a predetermined aperture value and the photometricoutputs are corrected on the basis of the reflection rate distributionobtained at that time.

FIG. 34 is a block diagram of a camera according to a sixth embodimentof the present invention. Photometric element 15 (a first photometricmeans) is constituted by five regions 15a˜15e, and provides photometricoutputs by segmenting the object field into five regions when the flashapparatus is not flashed. Its position in the camera is almost the sameas that of the first photometric means as shown in FIG. 4.

Five outputs of this photometric element 15 are inputted into a fieldcategorization apparatus 77. This field categorization apparats 77categorizes the field into two patterns, "bright" or "dark". Note thatits detail will be described later by way of FIG. 35.

A calculator 78 determines the extent of weighting at the time of TTLlight adjusting (main flash), in accordance with an algorithm which willbe described later by way of FIGS. 36 and 37, and outputs the result tothe weighted light adjusting circuit 28. Also, from five outputs of thephotometric element 15, an appropriate exposure value is calculated bymeans of the calculator 78 and is transmitted to exposure control means68 where controlling for a shutter 17 and an aperture 25 are carriedout.

Further, photometric element 7 (second photometric means) is alsoconstituted by five regions 7a˜7e and measures the reflected light fromthe object field by segmenting the object field into five regions whenthe flash means 16 are caused to flash. Its position in the camera isalmost the same as that of the second photometric element 7 as shown inFIG. 4. This photometric element 7 is positioned such that the objectfield segmented by its five regions corresponds to the object fieldsegmented by the five regions of the photometric element 15.

Flash means 16 is controlled by flash control means 29 and carries outpreliminary flash and main flash.

Next, the operation will be described in detail by way of FIGS. 35˜38.FIG. 35 shows an example of algorithm for the field categorization means77; FIGS. 36 and 37 show examples of algorithm for the calculation means78; and FIG. 38 show an example of circuit for the weighted lightadjusting circuit 28. And, each of the above described means iscontrolled by a micro computer.

Referring first to FIG. 35, the operation of the field categorizationmeans 77 is described. At step S101 (hereinafter "step" is omitted),when release button 24 is turned on, the program proceeds to S102 atwhich luminance values BVn (n=1˜5) of the five outputs of thephotometric element 15 are read. Then, at S103, an average luminancevalue BM is calculated from these as follows: ##EQU5## At S104, it isseen if the average luminance value BM exceeds 7. The program proceedsto S111 when BM≧7 while it proceeds to S131 when BM<7.

Then, when luminance condition of the object field is determined asabove by the field categorization means the calculation means 38accordingly performs controlling as shown in FIG. 36 and FIG. 37.

FIG. 36 shows a case of proceeding to Sill.

Initial values of n, M are set as 0 at Sl12 and n=n+1 is set at S113.

Then, at S114, a comparison is made between BVn and 111/3(BV). IfBVn≦111/3(BV), Pn=1 is set at S115 and M=M+1 is set at S117. This M isto represent the number among five BVn which are not more than 111/3.

If BVn>111/3(BV), Pn=0 is set at S116. Until n exceeds 5 at S118, theabove routine S113 to S118 is repeated.

When n exceeds 5, a comparison is made between M and 5 at S119. If M=5,it is a case where there is no very high luminance output exceeding111/3(BV) among BVn, and the program proceeds to a large luminancedifference block which consists of S121˜S124.

If M≠5 at S119, it is a case where one or more very high luminanceoutputs exceeding 111/3(BV) among BVn, and the program thus proceeds toS120 at which the extent of weighting Dn is determined. At S120, acalculation, Dn=Pn/M, is performed, where weights Dn corresponding tothe photometric regions which have provided very high luminanceexceeding 111/3(BV) are set as 0 while weights for the other regions maybe obtained as:

    Dn=1 / (number of regions not exceeding 111/3(BV)).

And this result is sent to S125.

Through the large luminance difference block consisting of S121˜S124,the maximum luminance difference A among the five outputs is calculatedat S121 as:

    Δ=MAX (BVn)-MIN(BVn), and

a comparison is made at S122 between Δ and 3. If Δ<3, i.e., when themaximum luminance difference Δ is small, the program proceeds to S124 atwhich the weights are set as Dn =1/5 for all five outputs and thisresult is sent to S125. If on the other hand Δ≧3, i.e., when the maximumluminance difference is large, the program proceeds to S123 at which theweight corresponding to the highest luminance (BVn=MAX) among the fiveoutputs is set as Dn=1/10, the weight corresponding to the lowestluminance (BVn=MIN) is set as Dn=3/10, and the weights for the threeremaining outputs are all set as Dn=2/10 and the result it sent to S125.

At S125, voltage values En corresponding to weights Dn as describedabove are calculated in accordance with the formula: En=K (1-Dn) Er. Kis the value corresponding to the ISO information to be inputted atS126, and Er is a predetermined constant voltage detail of which will bedescribed later with reference to FIG. 38.

FIG. 37 shows the case of proceeding to S131 because the object fieldhas been categorized as dark by the field categorization means as shownin FIG. 35. At S132, mirror up of the mirror 10 (see FIG. 4) andstropping down of the aperture 25 are carried out. The program thenproceeds to S133 at which a preliminary flash by the flash means 16 iseffected so that the reflected light from the object body due to thepreliminary flash passes through the photographing lens LE (FIG. 4), isreflected at the shutter blind surface 17 (FIG. 4), passes through thephotometric lens 8 (FIG. 4) and reaches the photometric element 7disposed at the position of the photometric means 7 (FIG. 4). Theelement surface of the photometric element 7 is segmented into fiveregions 7a˜7e and carries out photometry by segmenting the object fieldinto five regions.

At S134, an integrated amount Cn is obtained for a photometric output ofeach photometric region in the photometric element 7.

At S 135, the reflection rate distribution Rn of the object field isdetected from the following formula as: ##EQU6##

At S136 to S142, regions at which reflection rate distribution Rn isvery high (Rn>0.8) and regions at which that is very low (Rn<0.1) areextracted and are cut out. Photometric regions with very high reflectionrate distribution Rn are cut out because there is presumably behind thesubject (person) an object such as a gold-leafed folding screen or awhite wall which adversely affect the TTL light adjusting. Also,photometric regions with very low reflection rate distribution Rnrepresent a case where background of the subject (person) is for examplea landscape causing an emptiness which is also presumably a factoradversely affecting the TTL light adjusting.

Upon such cutting out, the reflection rate distribution Rn (n=1˜5) forthe cut out regions are replaced by 0 and do not contribute to thesubsequent calculations.

At S143, weights Dn are calculated on the basis of the reflection ratedistributions Rn (n=1˜5) after the cutting out as: ##EQU7##

Then, the program proceeds to S144 and S145 at which the above describedweights Dn are correspondingly converted into voltages En as:

    En=K(1-Dn)Er, and

are inputted to the weighted light adjusting circuit 28. K is the valuecorresponding to the ISO information to be inputted at S114, and Er is apredetermined constant voltage detail of which will be described laterwith reference to FIG. 38.

When the voltages En corresponding to the weight amounts are inputtedinto the weighted light adjusting circuit 28, at S146, a main flash bythe flash means 16 is carried out. At this time, the main mirror 11 isin its mirror up state and the aperture 25 of the lens is stopped downto the photographing aperture value. The reflected light of the mainflash from the object body passes through the lens LE (FIG. 4), isreflected at the film surface FI (FIG. 4), passes through thephotometric lens 8 (FIG. 4) and reaches the photometric element 7 asshown in FIG. 4. The photometric element 7 is segmented into fiveregions 7A˜7e and adjust the reflected light of the main flash from theobject field by segmenting into five regions. Note that the segmentingconfiguration of the object field by the photometric element 7 is causedto generally correspond to the segmenting configuration of the objectfield by the photometric element 15.

The reflected lights measured in segments at the photometric element 7are weighted at S147 by the weighted light adjusting circuit 28 and thenintegrated. And, when the total of the integrated amounts for the fiveregions has reached a predetermined amount, an emission stop signal isprovided, whereby the emission of the flash apparatus 16 is caused tostop via the flash control apparatus 29, and the program then proceedsto S148 where it ends.

A circuit diagram for the weighted light adjusting circuit 28 will nowbe described by way of FIG. 38.

When lights are incident on five photodiodes 7a˜7e which constitute thesecond photometric means 7, potentials corresponding to such quantitiesare outputted from OP-amps 835a˜835e and are applied to the bases of thetransistors 837a˜837e. Then, while collector currents flow in from Vcc40 via the condenser 75, such amounts are changed by the potentials ofthe variable power source 838a˜838e. The potentials of these variablepower sources 838a˜838e are set from the voltage values En outputtedfrom the CPU portion 78a of the the calculation means 78 as describedabove via D/A converters 823b˜823f. For example, when the portion 15a ofthe first photometric means 15 is of very high luminance exceedingBV=111/3, D1 becomes 0 where a large value is set as El. Then, theamount of collector current flowing into the transistor 837a becomessmall which as a result does not contribute very much to the chargecumulation at the condenser 75. Comparator 58 is designed to provide theemission stop signal to the flash control means 29 when the potential atthe non-reversible input terminal side has exceeded the criterionpotential at the reversible input terminal side. Therefore, the factthat it does not contribute very much to the charge cumulation at thecondenser 75 means that the output from the photodiode 7a is assignedwith a low weight so that the effect of very high luminance is removed.Photodiodes 7b˜7e are as shown in the figure respectively provided witha circuit which is identical to the circuit consisting of 834a˜838a, andeach of these circuits is integrated with a collector of the transistor837 so as to be connected to the condenser 75. Accordingly, thephotodiode output of a region to which a high weight is assigned is morelikely to contribute to the charge cumulation at the condenser 75 andpredominantly determines the timing at which the emission stop signal isto be provided.

FIG. 39 shows ˜examples of element pattern combinations of the first andsecond photometric elements. Case 1, identical to the embodiment asshown in FIG. 34, indicates the fact that, when the oblique line portion15e is of high luminance, it suffices to assign a low weight to theoutput of the corresponding oblique line portion 7e, i.e., to lower thecontribution of the output of the photodiode 7e to the light adjustingoperation of the flash apparatus. Further, it is also possible toprohibit the output of the photodiode 7e so as to remove the effect ofthe oblique line portion 15e.

In Case 2, while the first photometric means is of a five-segmentedtype, the second photometric means is of a two-segmented type and onlythe center portions 79c and 80a correspond to each other. In this case,when any of the peripheral portions (79e for example) is of very highluminance, the weight for the whole peripheral portion 80b is reduced atthe time of TTL light adjusting. Such a combination is useful when thephotometric optical system of the second photometric means cannotsegment the object field very accurately

Case 3 shows an example where the first photometric means is not of asegmented photometry type. It is thereby shown that, when the firstphotometric means has detected a very high luminance, the peripheralportion 82b at which the main object is less likely to exist is assignedwith a lower weight.

In case 4, while the first photometric means is of five-segmented type,the second photometric means is segmented into three regions. This showsthat, when the portion 83e has detected a very high luminance, the wholeof the upper peripheral portion 84b is to be assigned with a low weight.Such a combination is effective when the photometric optical system ofthe second photometric means side watches the film surface from asubstantially oblique position as shown in FIG. 4 or when the objectfield can be accurately divided into top and bottom while it cannot bedivided very accurately into left and right.

While the embodiments of cameras according to the present invention havebeen described by way of the drawings, it is to be understood that thescope of the present invention is not limited to the embodiments asdescribed above and various changes and modifications are naturallypossible without departing from the spirit thereof.

According to the sixth embodiment of the present invention, the objectfield is categorized by the field categorization means, and, when theobject field is categorized as bright, regions at which high luminanceexists are extracted by measuring the steady light so that such regionsare assigned with low weights or cut out at the time of light adjustingfor the main flash. Thus a TTL light adjusting is possible with asuitable light emission. Also, while, at the time of photographing at aluminous scene, the metering of the preliminary flash becomes difficultin terms of quantity because the aperture is reduced in size and theratio of the flash to the steady light is also reduced, the problem at aluminous scene may be eliminated, without a preliminary flash, byemploying the system as described above

When it is categorized as dark, a preliminary flash is carried out bythe flash means and the reflected light therefrom is measured to detectthe reflection rate distribution for the object field. Then, regionswhich presumably cause an adverse effect for the TTL light adjusting areextracted, and these regions are cut out or assigned with lower weightsat the time of light adjusting for the main flash. Thereby, a TTL lightadjusting with a suitable light emission is possible also in this case.

Since, in this way, the camera automatically categorizes the objectfield by the field categorization means and automatically selects amethod of weighting for the light adjustment from a steady light systemand a preliminary flash system, an appropriate flash emission may becarried out for all the regions, from bright to dark.

I claim:
 1. A light emission control apparatus comprising:a flash devicecapable both of a preliminary flash to be emitted before a flashphotographing and of a main flash to be emitted for the flashphotographing; a light adjusting device having segmented light adjustingelements, for controlling a light emission of said flash device based onoutputs from said light adjusting elements; a photometric device formeasuring light from an object field; a field categorization device forcategorizing a luminance value condition of said object field at leastinto a first condition and a second condition by using outputs from saidphotometric device; and a calculation device for prohibiting apreliminary flash of said flash device and for carrying out weightingfor the outputs of said segmented light adjusting elements based on theoutputs from said photometric device when said object field iscategorized as in said first condition by said field categorizationdevice, and for effecting a preliminary flash of said flash device andfor carrying out weighting for the outputs of said segmented lightadjusting elements based on the outputs from said photometric devicewhen said object field is categorized as in said second condition.
 2. Alight emission control apparatus according to claim 1, wherein saidphotometric device comprises a segmented photometric system.
 3. A lightemission control apparatus according to claim 1, wherein said fieldcategorization device discriminates an object field as in said firstcondition when the average of the luminance values for the outputs ofsaid photometric device is at least a predetermined value but otherwisediscriminates an object field as in said second condition.
 4. A lightemission control apparatus according to claim 2, wherein said fieldcategorization device carries out a categorization by using an averageof two or more luminance values among a plurality of luminance valuesmeasured in segments by said photometric device.